Another gas gauge issue

Trying to button up the dash cluster on my 73 Sport project. I did the MAD bypass, installed a Sun volt gauge in place of the factory amp gauge, and it works. Added aftermarket oil pressure and water temp gauges, tying into the factory wiring for the feeds from the sending units. They work fine. Gas gauge in the dash does not work. Here's what I've done so far:
1 - checked voltage coming into the dash from the red wire at the round plug. Got voltage.
2 - Checked the connector behind the kick panel for the blue wire from the gas sending unit. Got voltage.
3 - checked the blue wire at the dash plug. Got voltage.
4 - had already replaced the IVR with a digital unit. Has voltage and the red indicator light flashes when energized.
5 - checked voltage at the gas gauge connectors. Got voltage.
6 - grounded the plug at the tank and turned ignition on for a short time. Gas gauge went to full immediately. Back to empty when ignition turned off.
Thinking the sending unit was bad, I dropped the tank to check it. With the Ohm meter on the connector pin and grounded against the flange, the Ohm meter reads 8.1 at full and transitions to 76.6 at empty. Do I look at replacing the gauge? Since they're pretty expensive, is there a test I've missed? Sorry for the long post, but I wanted to list all the checks I've done so far.